Hard case arranged for party activity (8)
I believe the answer is:
charades
'party activity' is the definition.
'charades' can be an answer for 'activity' (charades is a kind of activity). I am not certain of the 'party' bit.
'hard case arranged' is the wordplay.
'arranged' indicates anagramming the letters (letters rearranged).
'hard'+'case'='hardcase'
'hardcase' with letters rearranged gives 'CHARADES'.
'for' is the link.
Can you help me to learn more?
(Other definitions for charades that I've seen before include "Miming games" , "Miming parlour game" , "Game in which answers are acted out" , "Games like this" , "Guessing game where words are acted out" .)